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Author Topic: CB750K4 New project  (Read 2838 times)

Offline Rob62

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Re: CB750K4 New project
« Reply #45 on: January 08, 2018, 11:03:22 PM »
Bloody hell that looks a bit bent !!. Yeah the metal is pretty thin, i notice there are new ones for sale at DS but i was hoping to use the old ones..... I’ll have a word with the plater and see what he says, they aren’t badly rusted but like you say may be too pitted to prepare.

Offline Rob62

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Re: CB750K4 New project
« Reply #46 on: January 08, 2018, 11:05:20 PM »
Be careful with ordering a new master cylinder kit, a lot are listed but the wrong size. The two holes in the master cylinder need to be clear  ;)
Cheers Trigger. Actually i already moticed that one of the two holes in the base of the reservoir looks to be blind drilled which seems a bit odd, the other goes straight through into the bore.... inside the cylinder is quite clean and rust free it was only the circlip groove that was rusted in. Ill get my magnifying glass out and have a closer look at those holes....



You need a wire from a wire brush to poke in the hole that you think is blind, as it is not a blind hole  ;)

Ahhh...nice one, I’ll have a look..thanks for that !

Offline Trigger

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Re: CB750K4 New project
« Reply #47 on: January 08, 2018, 11:19:20 PM »
Did notice that your speedo has gained 5MPH  ;)

Offline Rob62

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Re: CB750K4 New project
« Reply #48 on: January 09, 2018, 07:51:15 AM »
Did notice that your speedo has gained 5MPH  ;)
:) thats just the camera angle, I havent removed either the needle or the faces..
Did have another look at that master cylinder this morning and i can see the little hole now that you pointed it out.... I’ll give it a gentle poke and a blow through with comp air.

Offline Rob62

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Re: CB750K4 New project
« Reply #49 on: January 12, 2018, 09:05:23 PM »
Stripped and cleaned the rear mudguard and light assembly tonight. No rechroming required although it does have some marking and slight pitting. It matches the rest of the bike....



Received a few goodies through the post today too

May remove the engine tomorrow... see how much time i get...

Offline Rob62

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Re: CB750K4 New project
« Reply #50 on: January 13, 2018, 06:18:09 PM »
Well, towed my bollocks off today trying to extract that engine.... I thought I would try the suggested method of laying the frame on its side and lifting it off the motor.... Well i had to call the cavalry (my twin brother) in the end and after an hour of straining and cursing we finally managed to lift the bugger free, what a pain, will have to come up with a better technique when its time to refit.



Will do a bit of final stripping the stand off etc tomorrow, and the swing arm pivot appears to be well stuck...

These are free to a good home if anybody wants them, they work but aren’t perfect, be ok for a winter hack
« Last Edit: January 13, 2018, 06:40:16 PM by Rob62 »

Offline Green1

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Re: CB750K4 New project
« Reply #51 on: January 13, 2018, 06:21:23 PM »
You want a completely bare frame before lifting the wheels are bloody heavy.  ;)
Current bikes
Honda CB750k1 Valley Green Metallic
Honda CB750k1 Candy Gold
Honda CB550k Candy Jade Green
Honda CB400 Parakeet Yellow
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Offline Trigger

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Re: CB750K4 New project
« Reply #52 on: January 13, 2018, 07:40:58 PM »
Even with a bare frame, it is easier with two. And if your points cover is in good nick, always remove it and its contents  ;)

Offline Rob62

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Re: CB750K4 New project
« Reply #53 on: January 13, 2018, 09:23:35 PM »
We did remove the wheels and forks after we realised it wasn’t going to simply lift off, it took a lot of jiggling about, i guess you could get a knack for doing it after a few attempts but this was my first.... I put some blocks down and an old towel to protect the points cover which has no rust but is a bit bent.. it will straighten out. I think I will revert to the honda workshop manual method for refitting i.e. lift the engine into the frame....

My next worry is the swing arm spindle as it didn't want to come out easily..... but other than that the whole bike has come apart fairly easily and most of it will be good enough to go straight back on after a good clean.. Im getting excited  :P

Offline K2-K6

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Re: CB750K4 New project
« Reply #54 on: January 13, 2018, 09:59:27 PM »
It is a bit like the Krypton factor to juggle those out,  especially that bit by the rear engine mount by the kickstart area as it's just got to be in the right place to pass the frame lugs.

You get just a bit more wiggle room if you take the exhaust stubs off the head as well,  it just allows you to rotate it slightly more to get clearance at that back point. I don't feel they are too bad upright if you've got two of you on it,  usually rap thick newspaper round frame rails and stick with gaffer tape to protect painted frame and motor then gently lift it in and you can rest it while you look which way to juggle it as you inch it across to the right place.

Offline Rob62

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Re: CB750K4 New project
« Reply #55 on: January 13, 2018, 10:09:16 PM »
Yep that sounds like a good plan... and you’re right it was the rear mounting getting in the way.

Offline Jamesh_sussex

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Re: CB750K4 New project
« Reply #56 on: January 13, 2018, 11:37:43 PM »
Great advice re. Removing exhaust stubs. I learnt this one the hard way - but removal of the stubs makes life a lot easier...

Offline Rob62

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Re: CB750K4 New project
« Reply #57 on: January 20, 2018, 10:00:40 PM »
Finished cleaning the frame today. It was crusted in chain lube and dirt round the lower and inside tubes. My original intention was to keep the bike original and avoid powder-coat. There is no rot but a few areas that will need a bit of touching up. I think its just about good enough to keep original




The swing arm will need powder coating, or re painting.... unfortunately there are too many scratches. Shame because i like the original decals. I notice that there are some for sale on ebay at reasonable prices but the one for the swing arm isnt 100% accurate ...
https://www.ebay.co.uk/itm/HONDA-CB750-FOUR-K3-K4-1973-1974-WARNING-KIT-DECALS/202163352220?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649
« Last Edit: January 22, 2018, 01:12:21 PM by Rob62 »

Offline Trigger

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Re: CB750K4 New project
« Reply #58 on: January 20, 2018, 10:15:56 PM »
Piki is a member on this forum, send him a PM and he will do you a SOHC members deal. If you send him a detailed picture of the decals, then he will do his best to copy it  ;)

Offline Woodside

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Re: CB750K4 New project
« Reply #59 on: January 21, 2018, 08:56:47 AM »
that ebay link is to piki's...but pm direct he is very very helpfull and his stickers are tops...

 

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